Color yielding photographic elements



Patented Apr. 2, 1946 I UNITED STATES PATENT OFF-ICE coma YmLnmGrngrooaarmo poration of Delaware No Drawing. Application March 31,1944,- Serial No. 528,942

9 Claims.

' polymer containing a plurality of hydroxyl groups and having aplurality of color-former; structural components and. in addition,containing light-sensitive silver salts. The invention also relates tomethods of making such elements and to processes for preparing dyeimages utilizing such layers.

Various types of elements for color photography using color-formers ordye intermediates which couple with the oxidation products of aromaticprimary amino developing agents during the deveiopment of silver imageshave been proposed. Among the proposed elements are those which consistof a gelatin-silver halide emulsion layer containing a dye intermediatecapable of color coupling development which is immobile or fast todiffusion. The intermediate may be substantive to gelatin by reason of agroup which lends substantivity to a dye-forming component, or the dyecomponents may have a high molecular weight group attached thereto whichrenders the entire molecule fast to diffusion. Other proposed elementsuse, in gelatino silver halide layers, color-formers which are dispersedin particles of water-permeable resins. In a variation, the resinparticles may also contain silver halide grains. These elements,however, have poor definition and, on enlargement or projection, colorgrains appear.

This invention has for an object the production of photographic elementswhich contain synthetic color-formers which are hydrophilic and have theability to disperse, and prevent coagulation and sedimentation of silversalts. Another object is to provide a photographic element for colorphotography which can be made in a simple and economical manner. Anotherobject is to provide photographic elements which are free from gelatinbinding agents. Still other objects will be apparent from the followingdescription of the inventlon.

It has been found that useful photographic compositions for theproduction of dye images which can be made by incorporatinglight-sensi-- tive silver salts into hydrophilicfilm-forming syntheticpolymers containing as a part of their molecular structure, color-formernuclei or components capable oi forming indophenol or ammethine dyes.The light-sensitive silver salts can be incorporated by admixingdispersed, preformed reducible silver salts with the hydrophilicsynthetic polymer color-formers, or the 511- ver salts may be formed .orprecipitated in the hydrophilic synthetic polymer color-formers. Thecompositions comprising the hydrophilic filmtorming synthetic polymercolor-formers and light-sensitive silver salts can be deposited on abase or support to form an element suitable for photographic exposureand development. BY hydrophilic film-forming synthetic color-tormingpolymers" in this application is meant synthetic organic polymericcolor-formers which contain a plurality of non-phenolic hydroxyl groupsas the predominant hydrophilic group and which include in theirmolecular structure nuclei which are capable of forming an azo-inethineor indophenol dye on color-coupling development and which, in the formof thin layers, e. g., .1 to 10 microns in thickness, are insoluble inwater at 30 C; but are freely water-permeable. They should, moreover, besoluble to the extent of at least 5 parts by weight in 100 parts of aboiling aqueous solution containing less' than 50%, and preferably lessthan 25% of ethanol.

In accordance with the invention, the hydrophilie light-sensitivelayersand compositions are composed of hydrophilic synthetic linearhydroxyl-polmer color-formers which contain a plurality of free hydroxylgroups and a plurality of color-. former nuclei capable of formingindophenol or azomethine dyes. as a part of their molecular structure.The polymers of this aspect contain a plurality of non-phenolic hydroxylgroups as the predominant hydrophilic group. The hydroxyl polymers ingeneral should contain at least 1 aliphatic hydroxyl group to every 8carbon atoms of the poh'mer chain, 1. e., 12.5 hydroxyl groups for everychain atoms, and preberably, 1 to 2 hydroxyl groups for every 5 chainatoms 1. e., between 25 and 50 hydroxyl groups per each 100 chain atoms.The color-former nucleu or groups are attached to the polymer chaineither directly or indirectly. It is preerred that for every 100 chainatoms, between 1 and 35 color former nuclei be present. These 5;preferred hydroxyl polymer color-formers, moreover, have a polymer chaincontaining more than 200 atoms.

Suitable synthetic hydroxyl polymers that may be connected tocolor-forming nuclei to produce the hydrophilic color-forming hydroxylpolymers of the present invention include hydrolyzed polyvinyl esters,i. e., polyvinyl alcohols, hydrolyzed interpolymers of vinyl esters, e.g., vinyl acetate, vinyl propionate, and vinyl butyrate, etc., witholefins, e. g., ethylene, propylene, butane-l, and other vinylcompounds, e. g., acrylic acid, acrylic acid alkyl esters, alkylmethacrylates, vinyl chloride, vinyl cyanide, and maleic anhydride, andalso the partial esters, ethers, and acetals of such polymers. Thesepolymers may be connected to the colorformer nuclei by various chemicalgroupings or linkages, such as, for example, carbonamide, sulfonamide,amino groups, acetal, ester, ether linkages, etc.

The color-former nuclei or components of the above synthetic polymershave as active coupling groups a structure, which may be repre sented asno-(o=cli) 11:

where n is 0 or 1. This structure is found in color formers whichcontain a reactive acyclic or intracyclic methylene group and inaromatic hydroxyl compounds. These groups occur in phenols (includinghaphthols), acylacetarylides. cyanoacetarylides, beta-k'eto-esters,pyrazolones, N-homophthalylamines, coumaranones, indoxyls, thioindoxyls,etc. The reactive groups may also be termed reactive methylene, reactiveethenol and reactive 4-hydroxy-1,3-butadienyl groups. In all of thecolor-former nuclei the hydrogen atoms in the coupling position may bereplaced by groups which are readily eliminated in the couplingreaction, e. g., halogen, e. g., C1 and Br, sulfonic acid, carbox'ylicacid, etc.

Suitable compositions for the radiation-sensitive layers of photographicelements can be made by precipitating the silver halide in thehydrophilic synthetic polymer color-formers of the above described type.They can be advantageously made by mixing a viscous aqueous solution ofthe hydrophilic color formers with an aqueous solution of awater-soluble metal halide and subsequently with an aqueous solution ofa soluble silver salt. As a resu1t,, silver halides are precipitated andthe resulting silver halide dispersions, after suitable treatment suchas coagulation, ripening, washing and digesting, are coated from anaqueous solution which may contain methyl or ethyl alcohol onto asuitable support, such as a film base or support which may be paper,glass, metal or a cellulose ether or ester or a synthetic resin, e. g.,polyvinyl acetals, superpolyamides, e. g., nylon, etc. sensitizing dyescan be incorporated into the compositions before coating or theresulting layers can be bathed or impregnated with a solution aresensitizing dye, e. g., an acetone or alcohol solution.

The hem-sensitive color-yielding elements 0! this invention constitute anovel type of. photo graphic article in that they contain but twoconstituents in the light-sensitive layers or strata, (l)light-sensitive silver salts and (2) the hydrophilic synthetic polymercolor-former, which acts as a dispersing and protective colloid bindingagent for the silver salts.

Multilayer elements tor-color photography can be similarly made byccatingsuccessively on a film support similar hydroplaiic color-tamersilver halide layers. The silver salts and sensitizing dyes should be sochosen with respect to the hydrophillc synthetic polymer color formersthat the layers, when arranged in the element. are sensitive todifferent regions of the spectrum and yield dyes of different spectralabsorption. Filter layers can be used to control the selective action ofthe layers to light.

In the case of multilayer elements for threecolor photography, thelight-sensitive colorforming layers and a yellow filter layer may bearranged and sensitized in the same manner as the gelatino silver halidecolor-former layers described in U. s. P. 2,179,234 but utilizing threediflerent hydrophilic synthetic polymer colorformers of the above type.One of the polymers may contain color former groups which form ablue-green indophenol or azomethine dye upon color coupling developmentof a silver salt image formed in the layer, e. g., with a primaryaromatic amino color developing agent. A sensitizing dye which confersred sensitivity thereto is added and the resulting composition is coatedonto a transparent film base and dried. A second layer composed of ahydrophilic synthetic polymer color former of the above type which iscapable of forming a magenta indophenol or azomethine dye upon-colorcoupling development of a silver salt image for-med in the layercontaining a sensitizing dye which renders it sensitive to the greenregion of the spectrum, is coated on the first layer. On the secondlayer is coated a water permeable colloid, e. g., polyvinyl alcohol,etc., containing a removable yellow filter dye. On this layer may becoated a layer of a hydrophilic synthetic polymer color-former of theabove type capable of forming a yellow indophenol or azomethine dye uponcolor coupling development of light-sensitive silver salts contained insuch layer which are sensitive to the blue region of the spectrum.

The invention will be further illustrated but is not intended to belimited by the following examples wherein all parts are by weight, alltemperatures centlgrade, and all solutions aqueous unless otherwiseindicated, and all radiations which will expose or fog thelight-sensitive silver halides are excluded.

Example I A mixture of 106 parts of polyvinyl alcohol having a viscosityof 18-28 centipoises in a 4% aqueous solution at 20, 200 parts ofsalicylaldehyde, 500 parts of dioxan, and 10 parts or phosphoric acid isstirred at 85 for five hours. diluted with 1000 parts of acetone, andfiltered. The white powder is washed by decantation in moo-part portionsof acetone 6 times for 1 hour each, then filtered and dried to give 140parts of a fine white powder. Ten parts of this powder isdissolved bystirring in parts of 40% ethanolwater at 80 for hour. To 40 parts ofthis solution is added 40 parts of water, 5 parts of 1% aqueous sodiumdodecyl sulfate, and 5 parts of concentrated ammonia water. The mixtureis stirred at 45 while adding 20 parts of 3N silver nitrate and 23 partsof 3N ammonium bromidel/lON potassium iodide simultaneously during fiveminutes. After stirring a total of 15 minutes, the silver halidedispersion is allowed to cool and mixed with 106 parts or acetone whichprecipitates the binding agent containing dispersed light-sensitivesilver halides. After pouring on the liquid, soft rubbery polymer massis washed for one -half hour in running water to remove the solublesalts, then the remaining 60 parts of the original polymer solution isadded, together withparts of ethanol and 1 part of 10% aqueous potassiumbromide, and the whole mixture stirred at 58 for one-half hour, afterwhich it may be used directly or stored. This light-sensitive dispersionis coated on paper or a film base and exposed to a colored object. It isthen developed in the following solution:

Parts p-Aminodiethylaniline hydrochloride 2 Sodium sulfite 3 Sodiumcarbonate 20 Water To make 1,000

made by dissolving the constituents in 500 parts of water and dilutionof the solution to 1000 parts. It is then washed, bleached in 4%potassium ferricyanide, and fixed whereby a strong blue-green negativeimage is obtained.

Example II A coating composition was prepared by compounding thefollowing solution:

Acetal of polyvinyl alcohol with allylsalicylaldehyde andphthalaldehydic acid (U. S. P. 2,310,943, Example X) g 5 Dlmethylformamide cc Sodium hydroxide (5 N.) cc 1.5 Water cc 250 The solutionwas heated to 85 F. and 25 cc. of

water containing 1.5 g. of ammonium bromide added. To the resultingsolution in darkness were added with stirring 25 cc. of water containing2.5

g. of silver nitrate and Just enough ammonium p-Amino-N-diethylanilinegrams 2 Sodium carbonate (anhydrous) do d Sodium sulfite (anhydrous) do1 Potassium bromide do 2 Water to make -c- 1,000

A blue-green positive dye image formed in situ with the metallic silver.Upon removal of the silver and silver salts by treatment of the elementin 4% potassium ierricyanide and hypo solutions, a blue-green dye imageremained.

Example III A dye forming coating composition of the followingcomposition was prepared:

The modified acetal of Example VI of U. S. P.

2,310,943 g 5 Ethanol cc 15 Water c 15 Sodium hydroxide (5 N aqueous) cc1.5

The solution was heated to 80 F. and '75 cc. of water containing 1.5 g.of ammonium bromide added. To the resulting solution maintained underconditions of darkness were added 25 cc. of water containing 2.5 g. ofsilver nitrate and just enough ammonium hydroxide to make it basic,while stirring. The resulting composition was digested for 20 minutes atabout 100 F. and then coated on a gelatin subbed cellulose acetate filmbase. The film was exposed through a negative and developed in asolution of the type described in Example I and then the silver andsilver salts were removed in like manner tothat example whereby a yellowdye image remained.

The elements can be developed by a reversal process, it desired. Thus,an exposed element can be treated for a period 01. five minutes withintermittent agitation in a non-color forming developer of the formula:

N-methyl-p-aminophenol /2 sulfate grams 5.0 Hydroquinone do 7.5 Sodiumsulfite do 60.0 Potassium bromide do 4.5 Water to cc 1,000.0

After washing in the dark for ten minutes, the film is exposed to lightand developed for ten minutes in a color-developer of the followingcomposition:

p-Amino-N-diethylaniline hydrochloride grams 2.0 Sodium carbonate(anhydrous) do 20.0 Sodium sulfite do 0.5 Water to cc 1,000.0

After washing for 15 minutes in running water the film is bleached inneutral potassium ferricyanide, rinsed, fixed in plain hypo, washed anddried. A reversed dye image remains at the points where the reversedsilver image was formed.

Example IV A mixture of 100 parts of polyvinyl alcohol of mediumviscosity, 200 parts of salicylaldehyde, 500 parts of dioxan, and tenparts of phosphoric acid is stirredat 85" for five hours, diluted with1000 parts of acetone, and filtered. The white powder is washed bydecantation in 1000-part portions of acetone six times for one houreach, then filtered and dried togive 140 parts of a fine white powderwhich is a salicylaldehyde acetal of polyvinyl aldehyde containing inexcess of one acetal group per 20 hydroxyl groups. Ten parts of thispowder is dissolved by stirring in parts of 40% ethanol-water at 80 forone-half hour. To 40 parts of this solution is added 40 parts of waterand 5 parts of concentrated ammonia water. The mixture is stirred at 45C. while adding 20 parts of 3N silver nitrate and 23 parts of 3Nammonium bromide-l/ION potassium iodide simultaneously during fiveminutes. After stirring a total of 15 minutes, the silver halidedispersion is allowed to cool and mixed with parts of acetone whichprecipitates the binding agent containing dispersed light-sensitivesilver halides. After pouring of! the liquid, the soft rubbery polymermass is washed for one-half hour in running water to remove the solublesalts, then the remaining 60 parts of the original polymer solution, inwhich was incorporated 0.01 part of allyl thiourea, is added, togetherwith '70 parts of ethanol and one part of 10% potassium bromide, and thewhole mixture stirred at 58 for one-half hour, after which it may beused directly or stored. This light-sensitive solution is coated onpaper or film base and exposed to a colored object. It is then followedby washing, bleaching. in 4% potassium ferricyanide, and fixing, andyields a strong blue- (5' greennegative image.

Eaxzmple V Ten parts of the material described and used in Example III,U. S. P. 2,320,422 (saponified polyglycerol treated witho-hydroxy-phenvl acetaldehyde) is dissolved in 100 parts of dilutealkali. Five grams of light-sensitive silver halide precipitateddirectly in the polymer and coated onto a film base yields a blue imagewhen the resulting element is exposed and developed in primary aromaticamino developing agent as in Example 1.

Example VI Ten parts of the condensate obtained from polyvinyl alcoholacetalized with m-aminobenzaldehyde and condensed withphenylmethylpyrazolone carboxylic acid (described in U. S. P. 2,320,422,Example VIII) is dissolved in 200 parts of dilute alkali solution andsilver bromide precipitated within the polymer. A layer of this materialyields a magenta dyestufl image in a primary aromatic amino developingsolution.

Example VII Fifteen g. of the product obtained from polyvinyl alcoholacetalized with aminobenzaldehyde and condensed withacetoacetaminophenyl carboxylic acid (described in Example IX of U. S.P. 2,320,422) is dissolved in 250 parts of mild alkali solution. To thisare added 20 parts of 3N KBr followed by parts of ammoniacal 3N AKNO indarkness. A layer of the material when exposed and developed in aprimary aromatic amino developing solution yields a yellow dyestufl'image.

Example VIII A multilayer three-color film may be prepared as follows:Coat in order thin layers from aqueous ethano1 solutions of thefollowing compositions:

1. The light-sensitive color-former dispersion of Example I sensitizedto red with 1,l'-diethyl- 2,2'-naphthcarbo-cyanine iodide.

2. Hardened polyvinyl alcohol.

3. The light-sensitive composition of Example VI sensitized to greenwith l,1'-diethyl-2,2'- cyanine iodide.

4. Hardened polyvinyl alcohol containing a yellow filter dye or pigmentor colloidal silver.

5. The light-sensitive composition of Example VII sensitive to blueonly.

This film when exposed to colored objects can be developed to a colorimage in a primary aromatic amino developing solution of Example I togive a three-color picture in complementary colors upon removal of thesilver and silver salts. Alternatively, the film may be processed by areversal method as in Example III whereby a reproduction of the originalscene is obtained.

Example IX A hydrophilic film-forming acetal of a hydroxyl polymer isprepared as in Example I using a hydrolyzed ethylene/vinyl acetatelnterpolymer oi mol ratio of about 0.1 of ethylene to 1 of vinylacetate, prepared by interpolymerizing ethylene and vinyl acetate asdescribed in Example V of application Serial No. 446,116 followed byalkali catalyzed methanolysis as described in Example XI of applicationSerial No. 446,114 and continuation application thereof Serial No.577,736, filed February 13, 1945, now United States Patent 2,386,437, inplace of the alcohol. Ten parts of the resulting color-forming polymeris dissolved by stirring in 90 Parts of 40% ethanol-water at 80 C. forone hour. To this is added 80 part: of

water, five parts of 1% sodium lauryl sulfate, five parts ofconcentrated ammonia, 45 parts of 3N ammonium bromide-l /10N potassiumiodide and the solution stirred at 45 while adding 40 parts of 3N silvernitrate containing 40 parts of water and five parts of 1% sodium laurylsulfate during ten minutes. After stirring a total of 20 minutes, thesilver halide dispersion is allowed to cool and mixed with 200 parts ofacetone which precipitates the binding agent containing dispersedlight-sensitive silver halide. To this, after washing in water for onehalf hour and draining, is added a solution of ten parts of the polymerdissolved in parts of 50% ethanol water and two parts of 10% potassiumbromide solution and the mixture stirred at 58 C. for one-half hour.This coating composition is employed in place of the correspondingmaterial in Example 1, and strong blue-green negative images areobtained by photographic processing in the same way as in that example.

A multilayer film can be made by coating compositions of the typedisclosed and a yellow filter layer in order onto a cellulose acetatefilm base after adding suitable sensitizers as described above so thatthe layers of the resulting element are disposed and sensitized so thateach layer records the light from about one-third of the visiblespectrum. Such multilayer film elements free from gelatin-color-formerlayers can be processed to a color picture after the manner described inU. S. P. 2,179,234.

In place of the specific hydrophilic synthetic polymer color-formersdescribed above, can be substituted various other high molecular weighthydrophilic film-forming synthetic polymer coloriormers having thegeneral characteristics set forth above. The suitable color-formers haveas an integral part of their molecular structure, color-former nucleieither as links in the main polymer chain or as lateral substituentsbonded to recurring atoms or groups of the molecule. The color-formernuclei may contain phenolic hydroxyl groups or intracyclic or acyclicreactive methylene groups which render them capable of coupling with theoxidation products of an aromatic primary amino color developing agentto form an indophenol or azomethine dye. They are further characterizedby having a softening point above 40 C., being insoluble in' water andphotographic developing and fixing solutions at 25 C. and below butbeing soluble to the extent of at least 5% in boiling water or boilingwater containing less than 50% of ethanol and permeable to water andphotographic processing solutions. In addition, the polymericcolorformers are essentially colorless but are capable of formingcoherent, transparent, supported nontacky films and are free fromadverse action on light-sensitive silver halides.

Suitable additional hydrophilic synthetic polymer color-formers havingsuch characteristics are disclosed in U. S. Patents 2,310,943 and2,320,422 and may be utilized in the single layer or mutilayer elementsof this invention.

Various other hydroxy1 polymers can be used as a source of thehydrophilic color-forming hydroxy'l formers. The materials in generalshould have at. least 30% of the weight thereof represented by CHOH orCH2OH groups. Suitable materials include polyvinyl alcohol, hydro lyzedinter-polymers of vinyl acetate with acrylates, methacrylates, and othervinyl compounds, e. g., vinyl chloride or vinyl cyanide; also any of theabove compounds having up to 40% of the hydroxyl groups converted toethers, e. g., methyl. ethyl, hydroxyethyl, etc., or to esters, e. g.,acetate, propionate, butyrate, etc., or to acetals, e. g., formals,acetals, propionals, butyrals, benzals, etc., or any other suitablegroup. Of all these materials, however. the preferred binding agents ofthis invention are prepared from the vinyl type polymer in which thpolymer chain consists essentially of carbon to carbon linkages. Theseare desirable because the'polymers are more stable and resistdegradation or breaking of the polymer chain in the reaction involvinglinkage of the color formers and because color-forming hydroxyl polymersof this type form thin fihns of great toughness.

A high water solubility of the original polymer does not prevent its usein the preparation of the hydrophilic color former of the presentinvention since the introduction of dye intermediate nuclei usuallydecreases the cold water solubility to the point Where the coated filmsare no longer softened excessively in water. However, if the bindingagent has undesirably high water sensitivity, this can be controlled bythe introduction of other groups such as esters, e. g., acetates.propionates, benzoates, ether groups, or metal groups, etc. Similarly,if the binding agent does not have sufficiently high water sensitivityor so]- ubility, this can be improved by the introduction ofsolubilizing groups. For example, the carboxylic or sulfonlc acid groupscan be introduced by acetal formation with phthalaldehydic acid,o-sulfobenzaldehyde, or acids of the type cno (cm) .coon

or by partial esterification with phthalic or succinic acid, or byetheriflcation with glycolic acid. or by use of a dye intermediatenucleus containing such solubilizing groups. Any of the above groups canbe introduced either before or after introduction of the color-forminggroups into the polymer.

In addition to the color-former groups or components of the abovepolymeric color-formers, other of such groups may be employed. Thus, thedye intermediate nucleus may be any aromatic phenolic compound having acoupling position available ortho or para to the activating group or anyactive methylene compound, 1. e., a compound having a CH:-- groupactivated by two unsaturated groups taken from the class of be utilizedas a direct taking stock in the colordevelopment process as described inthe above examples, but they are useful in duplicating or copying. Forinstance, the multilayer film of Example VIII may be processed as inExample I to a color negative, then printed onto a similar film withwhite light or by exposure with blue, green, and red light controlled bysuitable filters adjusted to the spectral qualities of the dyes andcolor sensitizers and the printed material again Processed as in ExampleI to a color positive. A number of color positives may be produced froma single color negative. Similarly, by using reversal processing as inExample VIII for both taking and printing steps, color positives can beproduced. In this way also any number of color print can b produced. Thecolo negatives or positives produced according to this invention canalso be employed in securing separation negatives or positives by knownprocesses of color separation.

The invention is obviously not limited to the use of the specific colorcoupling developing agents of the above examples. On the contrary,various other developing agents of this type may be substituted in likemanner. A number of useful color developing agent are disclosed in thepatents listed in the preceding paragraphs.

Various materials may be added to the novel hydrophilic syntheticpolymer color-former silver salt dispersions such as general emulsion orsulfur sensitizers, e. g., allyl thiourea, allyl isothiocyanate, sodiumthiosulfate, etc.; optical sensitizers such as cyanine,1,1-diethyl-4,4'-cyanine iodide, 1,1'-diethyl-s,4'-cyanine iodide,1,1'-diethyl-2,2'-carbocyanine iodide, l',3-diethylthia- 4'-carbocyanineiodide and other methine and polymethine cyanine dyes, kryptocyanines,merocyanines, pseudo-cyanines, etc.

The hydrophilic'film forming synthetic polymer color-formers of thisinvention possess a number of useful properties, among which can bementioned (1) ability to disperse, prevent coagulation and sedimentationof silver salts, (2) freedom from adverse action on radiation-sensitivesilver salts, (3) adequate solubility in solvents, e. g.,water,'ethanol, etc., for coating, (4) a relatively high softeningpoint, (e. g., above 50 C.), (5) transparency and freedom from color,(6) insolubilityand freedom from softening in water at moderatetemperatures, (e. g., below' 20 0.), ('7) ready permeability to waterand photographic processing solutions at temperatures in theneighborhood of 20 C., and (8) ability to form a strong, coherent,supported film.

An important advantage of the invention resides in the fact that thehydrophilic color-former layers produce the maximum color densitiesobtainable from the amount of silver salt reduced by. development. Thisadmits of a decided saving in silver halides without sacrificing thequality of the dye image. Thinner coatings can be used which is of majorimportance in multilayer elements, because the innermost layers aresubstantiallyin thesame plane as the outermost layers The less, silverhalide the outer layers contain, the less scattering of light there is,and the more light passes through to the innermost layers. This resultsin more sensitive films. hav-- ing a higher degree .of definition andresolution than is obtainable by the use of immobile or non-diffusingcolor-formers in gelatin layers.

In contrast to gelatin, which is non-uniform and varies from lot to lotin respect to the sensitizing action on silver halides, the presenthydrophilicsynthetic pclymerf color -formers are uniform and-thesensitivity -to light of the silver haiides'dispersedthereincan beaccurately controlled by; adii n tmeasured amounts of sensitizing agentsf ,Inggdgiitiomthe color-yielding silver salt compositions-in -thepresent invention are much more stable than gelatin solutions and can bestored for longer periods of time without bein adversely afl'ectediInaddition, they are not sub- UCGI Lil HUUHI 6 asoasea.

ject to bacterial putrefaction as are gelatin-silver halidecompositions. Still other advantages will be apparent from the abovedescription of the invention.

As many apparently widely diflerent embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsthereof except as defined in the appended claims.

What is claimed is:

1. A photographic element comprising a support bearing at least onelayer composed of a hydrophilic, essentially colorless, syntheticpolymer color-former containing a plurality of aliphatic alcoholhydroxyl groups as the predominant hydrophilic groups and having as anintegral part of its molecular structure color-former nuclei containinga structure of the formula came where n is a number from the groupconsisting of and 1, said layer containing light-sensitive silverhalides.

2. A photographic element comprising a support bearing at least onelayer composed of a hydrophilic, essentially colorless, syntheticpolymer color-former having at least 12.5 aliphatic aicohol hydroxylgroups as the predominant hydrophilic groups and at least onecolor-former component containing an active dye coupling structure ofthe formula where n is a. number from the group consisting of 0 and 1for every 100' chain atoms, said layer containing light-sensitive silversalts".

3. A photographic element comprising a support bearing at least onelayer composed of a hydrophilic, essentially colorless; syntheticpolymer color-former having at least. 260 chain atoms at least 12.5aliphatic alcohol hydroxyl groups as the predominant hydrophilic groupsand at least one-color-former component containing an active dyecoupling structured thliormola where n is a number from the groupconsisting of 0 and 1, for every 100 chain atoms and being soluble tothe extent. of at. least five parts by weight in water containing from Ito of ethanol said layer containing light-sensitive silver halides.

4. A multilayer photographic element comprising a support bearing ayellow filter layer and three color-yielding layers composed of ahydropl'rilic', essentially colorless, synthetic polymer color-formercontaining a plurality of aliphatic hydroxyl groups as the predominanthydrophilic groups and having as an integral part of its molecularstructure color-former nuclei containing a structure of the formulawhere n is a number from the group consisting of 0 and 1, saidcolor-yielding layers being different and containing light-sensitivesilver halides and being so sensitized and arranged that theyeach'record about onn4hird or the visible spectrum and form acolordevelopedf dye which is complementary in color to the utilizedsensitivity of the respective layers.

5. A photographic element comprising a support hearing at least onelayer composed of a hydrophilic, essentially colorless, synthetic vinylalcohol polymer color-former having at least 200 chain atoms, at least12.5 hydroxyl groups, and at least one color-former component containingan active dye coupling structure of the formula where n is a number fromthe group consisting of 0 and 1, for every chain atoms and being solubleto the extent of at least five parts by weight in water containing from1 to 10% of ethanol, said layer containing light-sensitive silverhalides.

6. A photographic element comprising a support bearing at least onelayer composed of a hydrophilic, essentially colorless, synthetic vinylalcohol polymer color-former having at least 200 chain atoms, at least12.5 hydroxyl groups, and at least one color-former component containingan active dye coupling structure of the formula lal-e where n is anumber from the group consisting of 0 and 1, for every 100' chain atomsand being soluble to the extent of at least five parts by weight inwater containing from I to 10% of ethanol, said component beingconnected through acetal linkages to carbon atoms of the vinyl alcoholpolymer chain and said layer containing lightsensitive silver halides.

7. A photographic element comprising a support bearing at least onelayer composed of a hydrophilic, essentially colorles acetal of salicylaldehyde with polyvinyl alcohol having at least 200 carbon atoms, atleast 12.5 aliphatic hydroxyl groups, and at least one salicyl' aldehyderadical for every 100 chain atoms and being solubleto the extent of atleast five parts by weight in water containing from 1 to 10% of ethanol,said layer containing light-sensitive silver halides.

8. A photographic element comprising a support hearing at least onelayer composed of a hydrophillc, essentially colorless acetal ofo-acetoacetamidobenzaldehyde with polyvinyl alcohol having at least 200carbon atoms, at least 12.5

aliphatic hydroxyl groups, and at least oneo-acetoacetamidobenzaldehyderadical for every 100 chain atoms and being soluble to the extent of atleast five parts by weight'in water containing from 1 to 10% of ethanol,said layer containing light-sensitive silver halides.

9. A photographic element comprising a support hearing at least onelayer composed of a hydrophilic, essentially colorless acetal of mphenylmethylpyrazolonoyiamidobenzaldehyde with polyvinyl alcohol havingat least 200 carbon atoms, at least 12.5 aliphatic hydroxyl groups, andat least one m-phenylmethylpyrazolonylamidobenzaldehyde radical forevery 100 chain atoms and being soluble ,to the extent'ef at least fiveparts by weight in'water containingfrom 1 to 10 of ethanol, said. layercontaining light-sensitive silver halides.

ANDREW B. JENNINGS. OTIS WILLARD MURRAY- F. A. WHITE.

